Soybean is a good food material which has rich nutrients and is good for the health, so that various snack foods utilizing soybean have been developed. For example, a snack food in which dry soybean juice is used as a material is disclosed in Japanese laid-open patent application No. 48-85755, snack foods in which a residue of soybean juice extract or "Okara" which is a byproduct of the production of soybean juice, soybean oil, soybean protein or the like are disclosed in Japanese patent publication No. 56-34257, Japanese laid-open patent application No. 56-55154 or Japanese laid-open patent application No. 59-162837, and a snack food in which soybean protein is used as a material is disclosed in Japanese laid-open patent application No. 62-111640. Any of these utilizes only a part of the soybean material as a powder of soybean juice extracted from soybean, a residue of soybean juice extraction a soybean protein in which only a protein portion of soybean is used or the like, so that it is not intended to wholly utilize nutrients characteristic of soybean and distinct flavorful soybean taste. Therefore, these cannot reproduce the whole flavor and taste completely and are not necessarily sufficient to further emphasize the flavor and taste of soybean.
It is necessary for utilizing soybean "as a whole" to overcome several difficulties to obtain a snack food. An ideal soybean snack has not been realized in which substantially the whole part of soybean material is used, there is no disagreeable unripe odor characteristic of soybean, having a flavorful soybean taste characteristic of soybean as an expressed taste, having a good leavening property and a good mouth-feel, components from soybean being homogeneously distributed in the whole of the food. For example, in Japanese patent publication No. 55-2255, it is intended to utilize whole soybean to produce a baked confection, in which problems arising from physical property of soybean such as "bean-removal" are mainly intended to be avoided, soybean being ground before addition of cereal flours to treat with steam before molding in a shape of cylinder or soybean-like shape to dry to add to a material for rice confection, so that the components from soybean are not homogeneously distributed in the whole food in the resultant baked confection. Generally, when a snack is desired in which whole soybean is used, the content of the components from soybean is increased to express taste and flavor of soybean material, and the components from soybean are homogeneously distributed in the whole part of food, the leavening property of the snack worsens due to fat components which exist in the soybean material. In the above Japanese patent publication No. 55-2255, this problem is avoided by distributing the components from soybean in the whole food not homogeneously. In order to obtain a soybean material food of good mouth-feel without worsening the leavening property of snack, for example, as disclosed in Japanese patent publication No. 63-5067, a soybean material which suffered degreasing treatment is used. However, the degreasing treatment worsens the distinct flavor and taste of soybean. Even if a good leavening is obtained, it is difficult to obtain a soybean snack in which the flavor and taste of soybean can be emphasized to express.
As the components of taste and flavor of soybean material, a flavorful soybean taste characteristic of soybean are included as well as a disagreeable unripe odor characteristic of soybean which is not preferable as a flavor of food. When a snack which has an expressed soybean taste is made, the disagreeable unripe odor characteristic of soybean is simultaneously emphasized without special treatment, and such snack has no value as a product. Namely, in order to realize an ideal soybean snack, it is necessary that among the components of taste and flavor of soybean material only the disagreeable unripe odor characteristic of soybean is removed, to retain the flavorful soybean taste characteristic of soybean, and that scattering of other components than the disagreeable unripe odor during removing the disagreeable unripe odor is prevented, simultaneously with which problems arising from components are prevented which may affect the production of snack such as fat components which have not been removed to maintain the flavor and taste of soybean.
Conventionally, although it has been believed that soybean is good for the health, the disagreeable unripe odor characteristic of soybean has been hated, so that a snack of expressed soybean taste has been prevented. And soybean has a relatively large amount of fat which inhibits leavening and precludes a soft mouth-feel, so that a soybean snack of good taste has not been obtained. It is desired to provide a snack which does not have the disagreeable unripe odor characteristic of soybean, has the flavor of soybean, and has a soft mouth-feel.